Metal-eating plants could mine riches through roots

Why mine for metals when we can cultivate them? (Image&colon; Pierluigi Longo)

Plants that absorb metals from the soil could clean up old mines and allow farmers to harvest valuable resources without ruining the environment still more

ALAN BAKER squatted to get a closer look at the delicate white flowers that shouldn’t have been there. He knew that the soil in that part of England’s Peak District was laced with metals toxic to most plants. Yet here, in the desolate surroundings of an old lead mine, he had found spring sandwort flourishing.

That was 45 years ago and the flowers that Baker spotted on his hike have guided his career as a plant scientist. Over the years, he and his colleagues have shown how some plants can take up certain metals in such large quantities that it is possible to “grow” a crop of metals. The idea could help regenerate landscapes blighted by mining and help farmers improve poor soils. And with metal prices soaring amid ravenous global demand for diminishing resources, it might even become a mining technique in its own right.

Phytomining, as the approach is known, may be about to hit pay dirt. A US patent covering the idea is set to expire next year, and that could allow the technique to blossom, giving metal-loving plants plenty of scope to transform the landscape.

When Baker came across the carpet of spring sandwort, he was a 20-year-old biology student at Imperial College London. Realising how unusual the find was – people have known for centuries that metals and plants don’t usually mix – he decided …